Technical Field
The present disclosure relates to a debris removal device and a debris removal method, and particularly relates to a debris removal device and a debris removal method which are suitable for removing debris drifting in outer space, such as satellites and rockets which are not used anymore and are orbiting the Earth.
Description of the Related Art
Currently, artificial satellites, such as military satellites, communications satellites, scientific satellites, observation satellites, and navigation satellites, are orbiting for various purposes. When the artificial satellites break down and do not function anymore, or when they finish their assignments and reach the end of their service life, the artificial satellites are often left in orbit, forming debris (space junk). In addition, the wreckage of rockets and the like used for launching artificial satellites and the like are also left as debris in orbit. Currently, several thousand pieces or more of debris are orbiting, and are entering a self-multiplication stage, where the number of pieces is increased by natural collisions. To avoid the self-multiplication of debris, it is necessary to remove at least roughly five pieces of debris per year. The debris are attracted by the terrestrial gravitation, and eventually fall and disappear; however, the natural falling requires long periods of time, and it is not efficient. In this respect, methods for actively removing the debris have been already proposed.
Japanese Patent Application Publication No. 2010-285137 discloses a debris removal method in which a pressure reception device for receiving a trace amount of air and solar radiation pressure is formed of a film material having a circular or polygonal shape, and this pressure reception device is attached to space debris already orbiting in outer space or a spacecraft to be launched later by a cord. Thus, the space debris or the spacecraft which has been used is caused to fall down to the ground or to change its orbit to protect an important orbit.
International Publication No. WO2013/065795 discloses a debris removal method in which a debris removal device observes the motion of target debris, and calculates the capturing position and capturing attitude in which a harpoon can be shot into the target debris. Then, the debris removal device is moved to take the capturing position and the capturing attitude determined by the calculation, and then the harpoon is shot into the target debris. Afterwards, the target debris is decelerated.